Single-Cell Dynamics Reveals Sustained Growth during Diauxic Shifts
Open Access
- 30 April 2013
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 8 (4), e61686
- https://doi.org/10.1371/journal.pone.0061686
Abstract
Stochasticity in gene regulation has been characterized extensively, but how it affects cellular growth and fitness is less clear. We study the growth of E. coli cells as they shift from glucose to lactose metabolism, which is characterized by an obligatory growth arrest in bulk experiments that is termed the lag phase. Here, we follow the growth dynamics of individual cells at minute-resolution using a single-cell assay in a microfluidic device during this shift, while also monitoring lac expression. Mirroring the bulk results, the majority of cells displays a growth arrest upon glucose exhaustion, and resume when triggered by stochastic lac expression events. However, a significant fraction of cells maintains a high rate of elongation and displays no detectable growth lag during the shift. This ability to suppress the growth lag should provide important selective advantages when nutrients are scarce. Trajectories of individual cells display a highly non-linear relation between lac expression and growth, with only a fraction of fully induced levels being sufficient for achieving near maximal growth. A stochastic molecular model together with measured dependencies between nutrient concentration, lac expression level, and growth accurately reproduces the observed switching distributions. The results show that a growth arrest is not obligatory in the classic diauxic shift, and underscore that regulatory stochasticity ought to be considered in terms of its impact on growth and survival.Keywords
This publication has 45 references indexed in Scilit:
- Carbohydrate‐active enzymes exemplify entropic principles in metabolismMolecular Systems Biology, 2011
- Pre‐dispositions and epigenetic inheritance in the Escherichia coli lactose operon bistable switchMolecular Systems Biology, 2010
- Bacterial adaptation through distributed sensing of metabolic fluxesMolecular Systems Biology, 2010
- Microfluidic devices for measuring gene network dynamics in single cellsNature Reviews Genetics, 2009
- Using movies to analyse gene circuit dynamics in single cellsNature Reviews Microbiology, 2009
- A Stochastic Single-Molecule Event Triggers Phenotype Switching of a Bacterial CellScience, 2008
- Regulatory Control and the Costs and Benefits of Biochemical NoisePLoS Computational Biology, 2008
- A comprehensive library of fluorescent transcriptional reporters for Escherichia coliNature Methods, 2006
- Dynamics of single‐cell gene expressionMolecular Systems Biology, 2006
- THE GROWTH OF BACTERIAL CULTURESAnnual Review of Microbiology, 1949